Credit: Orbis Brakes Inc.
I am a car enthusiast, so when I hear that an improvement has been made with the help of NASA’s technology, I start investigating more about it. Usually, NASA's contributions are associated with technologies developed for its missions. This case is different, it rests on the curiosity, creativity, and expertise of one of its structural materials engineers at NASA’s Marshall Space Flight Center in Huntsville, Alabama[1].
The story goes that during the 2019-2020 pandemic, Jonathan Lee got interested in car and motorcycle disk brakes after learning about the design of the Orbit wheel hub motors of the Honda Civic Type R. Lee contacted the company to suggest some improvements and ended up collaboration on a project to develop the Periodic Wave Disk Brake Rotor[2].
Credit: NASA
Lee is a mechanical designer, working as a structural materials engineer for the Space Launch System. He is also a microgravity material scientist for the space station. His contributions to the automotive industry are well known in NASA's community. One of them, alloy NASA 398, brought him and his collaborator, Po Chen, to the Space Technology Hall of Fame in 2018. The creation of NASA 398 started in 1993. They wanted to create a lightweight alloy for combustion engine pistons capable of withstanding high temperatures and pressures to enable the engines to run more efficiently with reduced emissions[3].
The main improvement introduced by the new rotors is heat dissipation, which reduces the brake temperatures by 25%. This also could reduce pollution by emission of brake-dust particles, which according to Motortrend, can be reduced by 10,000 times if brake temperatures are kept below 350-375 oF[4].
Credit: Orbis Brakes Inc.
The new design has the added advantage of making them lighter. Less weight also means reliable stopping and even better gas mileage. Conventional rotors are usually made of steel, which makes them heavy. Lighter versions made of carbon ceramic come at a higher price. The new design, however, can make steel rotors 42% lighter than traditional cast iron rotors and with performance comparable to much more expensive carbon-ceramic brakes[3]. So besides the possibility to end up with an affordable rotor, the lower temperatures can also be translated to improved performance and longevity.
How does this work?
In its Nov 2020 NASA’s Technology Transfer Program publication, the Periodic Wave Disc Brake Rotor is described as a two-piece floating rotor assembly designed to further reduce the weight of the mounting hub and its rotational moment of inertia, while simultaneously minimizing the rotor's thermal expansion, stress, warping, or distortion experience during extreme frictional heating generated from repeated hard braking actions under high-speed racing conditions[5].
Credit: Brembo
Conventional brake discs are heavy because they consist of two metal plates cooled by air circulating between them. In this design, the air cooling takes place on the inside surfaces, but the outside are the surfaces heated by the friction with the brake pads. Lee wanted to directly cool these hot surfaces and eliminate one of the heavy discs from each of the vehicle’s four rotors.
Lee started with a single disc and added a series of small fins around the central hub. In this way, the spinning fins and the centrifugal force of the wheel push air into the depressions, causing a turbulent airflow that draws away heat. When the air flings out, this is pushed across the surface, where the brake pads make contact, cooling the rotor, the brake pads, and calipers.
He also added several long depressions around the braking surfaces, radiating from the center to create the regular, periodic pattern that gives the new Orbis technology its PeriodicWave brand name. These trenches in the braking surfaces also increase the available surface for air cooling by more than 30%. A second periodic wave is cut along the outer edge, giving the new rotor more surface area than the conventional circle to come into contact with the cool air flowing over it.
Credit: Orbis Brakes Inc.
There are added advantages to this new design. The trenches also reduce the weight and increase friction, making the brake pads less likely to slip and making braking more reliable. These trenches also provide a place for the air vortex to push water and road debris off the way, preventing these from getting between the pad and the rotor. Finally, a thin layer of black coating applied to surfaces that do not come into contact with the brake pads, like the inside of the troughs, can help the rotor radiate additional heat.
Although Orbis Brakes Inc. has been advertising the production and release of these rotors since 2022, these are not available yet. But the market has seen a surge of the lightweight pin-drive drilled rotors, some with scalloped edges. It is a matter of time for companies to come up with improved designs or for Orbis to finally start offering the NextWave rotor for high-performance cars like the Ford Mustang and some Tesla models. We will keep watching.
Credit: Tesla
References